Main body core set assembly and core box for a coupler body

ABSTRACT

A main body core box assembly for creating coupler head cores which are attachable to various shank cores includes a main body core box including two halves, each half including a pattern configured to form the outer walls of a first head core having a first shank core. A plug is insertable into an end of respective patterns to form a second, alternative head core having a first half of a connection joint attachable to a second shank core that includes a second half of the connection joint, the second shank core being different than the first shank core. The first half of the connection joint may be a male connector, where the plug includes a recess having an angled surface to create a notch on the male connector. The second half of the connection joint may be a female connector with a raised surface corresponding to the notch.

BACKGROUND

1. Technical Field

The present embodiments relate generally to the field of cores used in railroad coupler casting, and more specifically, to a main body core set assembly and core box that uses a plug in a pattern of the core box to form a head core with a connection joint adaptively insertable into a shank core different than the shank core normally formed integral with the head core.

2. Related Art

Railcar couplers are used to couple railcars together. Typical couplers used throughout North America are the Type-E and Type-F couplers, also referred to as SBE60 and SBE69 or E69 couplers, respectively. These couplers are normally produced through a green sand casting process, which offers a low-cost, high-production method for forming complex shapes. While the heads of these couplers are identical, the shanks differ. The Type-E shank is shorter and tapers while the Type-F shank remains about the same width and is much longer. FIGS. 3A and 3B show how the shanks of these two couplers differ while the heads are the same except. The guard arm piece in FIG. 3A attaches and is therefore not cast with the head. Accordingly, the Type-E and Type-F heads are identical or substantially identical.

In sand casting, a mold is created using a sand and binder mixture (i.e., molding sand). The binder allows the sand to retain a shape. The most common sand/binder mixture used for casting couplers is green sand, which consists of silica sand, organic binders and water. Green sand is used primarily due to its lower cost.

The mold typically comprises a cope portion (i.e., top half) and a drag portion (i.e., bottom half), which are separated along a straight or offset parting line. To form the cope and drag portions, patterns that define the cope and drag portions, respectively, of the coupler and a gating system are placed into separate flasks (or mold boxes). Cores that will be used to define the inner and exterior surfaces of the coupler casting may also be molded from patterns in respective halves of mold boxes in a separate molding process.

Molding sand is then packed around the patterns, to define mold cavities for the coupler and gating system, or in the case of cores, to define the features of the cores that will be used to define the inner and exterior surfaces of the coupler. Draft angles of three (3) degrees or more are machined into the pattern to ensure the pattern releases from the mold.

As mentioned, the molding process may be used to create cores to define the inside of the main body of the coupler. Even though the heads of the Type-E and Type-F couplers are identical, the main body cores for the Type-E and Type-F couplers are conventionally formed in different mold boxes because the Type-E main body core is formed with a head core integral with a shank core and the Type-F head core is formed separate from a longer shank core. Using different mold boxes for forming the Type-E and Type-F main body cores is inefficient in the manufacturing process. Furthermore, the Type-F shank is conventionally set independently and not locked to the head core, resulting in internal fins at the head- to-shank joint which sometimes results in a T-section internal to the shank. A T-section is undesirable because it affects the solidity of the corresponding part of the casting and can result in hot tears at the bottom of the horn-to-shank interface of the coupler.

After the patterns are removed from the main body coupler mold, the cores are placed into the mold (between the cope and drag portions). The mold is then closed and filled with hot liquid metal, which is poured into the mold via a down sprue. After the metal has been poured into the mold, the casting cools and contracts as it approaches a solid state. Risers, which are reservoirs of molten material, are placed at those areas of the casting that exhibit the highest contraction. The risers feed those areas as the casting cools to help minimize the formation of voids, which would otherwise occur. The risers are formed in the cope portion and can typically define openings, which allow gases to escape during pouring and cooling.

After solidification, the solidified metal (e.g., raw casting) is removed by breaking away the mold. The casting is then finished and cleaned via grinding, blasting, welding, heat treatment, or machining. These casting techniques have several disadvantages. The binders used in the in the molding sand can have a significant effect on the final product, as they control the dimensional stability, surface finish, solidification, and casting detail achievable in each specific process. In particular, couplers cast in green sand having a relatively poor dimensional stability and surface finish. These couplers may also exhibit a higher rate of defects due to solidification issues.

BRIEF DESCRIPTION OF THE DRAWINGS

The system may be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like-referenced numerals designate corresponding parts throughout the different views.

FIG. 1 is a perspective view of a set of cores, including a main body core, for use in casting a Type-E (SBE60) railcar coupler.

FIG. 2 is a perspective view of a set of cores, including main body and shank cores, for use in casting a Type-F (E69) railcar coupler.

FIG. 3A is a perspective view of a main body of a Type-E coupler.

FIG. 3B is a perspective view of a Type-E head and Type-F shank of a railcar coupler.

FIG. 4A is a perspective view of one half of a mold box and pattern for forming a Type-E main body core.

FIG. 4B is a perspective view of the opposite half of the mold box and pattern shown in FIG. 4A showing sliding insert pieces that create apertures used to form the lock guide and thrower lug.

FIG. 4C is a perspective view of the mold box and pattern of FIG. 4A, with a plug inserted in the pattern such as to truncate the shank core portion, and thus create a Type-E head mold adaptable for a Type-F shank core for casting a coupler.

FIG. 4D is a perspective view of the mold box and pattern of FIG. 4B, with a plug inserted to truncate the shank core portion together with the plug of FIG. 4C, and showing the same sliding insert pieces as FIG. 4B.

FIG. 5A is a perspective view of the plug shown in FIG. 4C.

FIG. 5B is a perspective view of the plug shown in FIG. 4D.

FIG. 6 is a perspective view of a Type-E main body core that results from the mold boxes and corresponding patterns of FIGS. 4A and 4B.

FIG. 7 is a perspective view of a Type-E head core adapted for a Type-F shank core, where the shank core is truncated with use of the plugs in the pattern mold as shown in FIGS. 4C and 4D.

FIG. 8A is a perspective view of a Type-E head core adapted for use with a Type-F shank core from a different angle than that of FIG. 7 with a male connector.

FIG. 8B is a perspective view of a female connector of a shank core into which the male connector of the adapted head core of FIG. 8A may be inserted.

FIG. 8C is side view of the male connector of FIG. 8A, showing exemplary dimensions.

FIG. 8D is a plan, end view of the female connector of FIG. 8B.

FIG. 9A is a perspective view of an exemplary shank core to which the male connection joint of the adapted head core of FIG. 8A may be inserted.

FIG. 9B is a perspective view of the adapted head core of FIG. 8A attached to the shank core of FIG. 9A.

FIG. 9C is a cross-section view of FIG. 9B showing a tight-fitting connection joint between the adapted head core of FIG. 8A and the shank core of FIG. 9A.

FIG. 10 is a side, perspective view of a Type-E head core adapted for a Type-F shank core showing angles of insertion and removal of insert pieces shown in FIGS. 4B and 4D.

FIG. 11A is a cross-section, perspective view of a first half a coupler head and shank showing a lock guide inside the coupler head.

FIG. 11B is a cross-section, perspective view of a second half of the coupler head and shank of FIG. 11A, showing a thrower lug inside on the coupler head.

FIG. 12 is a flow chart of a method for creating a main body core for casting a coupler body of a railcar coupler.

DETAILED DESCRIPTION

In some cases, well known structures, materials, or operations are not shown or described in detail. Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It will also be readily understood that the components of the embodiments as generally described and illustrated in the Figures herein could be arranged and designed in a wide variety of different configurations.

This application is related to U.S. patent application Ser. No. __/__,__, filed, _______ 2011 and entitled “Method and System for Manufacturing Railcar Couplers,” which is hereby incorporated by this reference in its entirety.

FIG. 1 shows a set of cores 10 for use in casting a Type-E (SBE60) railcar coupler 244 (FIG. 3A). The set of cores 10 may include, but is not limited to, a main body core 100, a cotter hole core 104, a lower shelf core 108, an upper guard arm core 112, a lower guard arm core 116, a hose support lug core 120, a rotary shaft core 124, a gating core 130, a slot core 134 and a butt end core 138. As discussed earlier, these cores are placed inside cope and drag mold portions that are used to cast the coupler. The Type-E railcar coupler 244 shown in FIG. 3A is the product of the casting. The main body core 100 includes an integrated shank core 102 portion of the main body core 100.

FIG. 2 shows a set of cores 20 for use in casting a Type-E/F (E69) railcar coupler 254 (FIG. 3B). The set of cores 20 may include, but not be limited to, a main body (or head) core 200, a shank core 204 including a shank core cope side 205 and a shank core drag side 207, an upper guard arm core 212, a lower guard arm core 216, a hose support lug core 220, a rotary shaft core 224, a gating core 230, a rear pin hole core 234 and a spherical butt end core 238. As discussed earlier, these cores are placed inside the cope and drag mold portions before casting. The Type-E/F railcar coupler 254 shown in FIG. 3B is the product of the casting. The shank core 204 is separate from the head core 200 in FIG. 2, but has been attached to the head core 200 as will be explained herein. As discussed with reference to the related art, the head core and shank cores 200 and 204 are conventionally set independently and not locked to each other, resulting in internal fins at the head-to-shank joint which sometimes results in a T-section internal to the shank. A T-section is undesirable because it affects the solidity of the corresponding part of the casting and can result in hot tears at the bottom of the horn-to-shank interface.

FIGS. 4A and 4B display, respectively, a first mold box 300 defining a first pattern 301 and a second mold box 310 defining a second pattern 311 for forming the main body core 100 (FIG. 6) used to cast the Type-E railcar coupler shown in FIG. 3A. The first and second patterns 301 and 311 will define the outer surface of the main body core and are not identical because the main body core 100 is not symmetrical about its center parting line.

Each pattern 301 and 311 defines a first slot 302 and a second slot 306. A lock guide insert piece 304 is slidably attached to the first slot 302 of at least one of the patterns such that the lock guide insert piece 304 may be inserted and withdrawn before and after molding in a semi-automated fashion. The action can be semi-automated because the angle and placement of the lock guide insert piece 304 is precise as guided by the first slot 302, but may still be positioned manually by either inserting or removing the lock guide insert piece 304. The lock guide insert piece 304 forms an aperture 346 (FIG. 6) in the main body (or head) core that will form a lock guide 340 (FIG. 11A) of the coupler head during casting. The lock guide insert piece 304 slides along the first slot 302 at an approximate 90-degree angle with respect to an axis 345 (FIG. 10) formed through the longitudinal center of each pattern (and head core), e.g., with respect to the longitudinal center of a shank portion 312 of each pattern. FIG. 10 best shows this angle as the lock guide insert piece 304 is illustrated with reference to the head core 200 and the axis 345 without the mold box or pattern.

A thrower lug insert piece 308 is slidably attached to the second slot 306 of at least one of the patterns such that the thrower lug insert piece 308 may be inserted and withdrawn before and after molding in a semi-automated fashion. The thrower lug insert piece 308 forms an aperture 348 (FIG. 7) in the main body (or head) core that will form a thrower lug 350 (FIG. 11B) of the coupler head during casting. The thrower lug insert piece 308 slides along the second slot 306 at an approximate 45-degree angle (FIG. 10) with respect to the axis 345 formed through the longitudinal center of each pattern (and head core), e.g., with respect to the longitudinal center of a shank portion 312 of each pattern.

Because the insertion and removal of the lock guide insert piece 304 and the thrower lug insert piece 308 is semi-automated, insertion thereof is guided to the correct location for each cycle of molding, and is easily removed manually before the next cycle. This fact and that the insert pieces 304 and 308 remain on the mold boxes 300 and 310 saves time, making the molding process faster for each core.

Furthermore, the lock guide insert piece 304 and the thrower lug insert piece 308 are designed with precision so that they fit tightly in the main core box slots 302 and 306, respectively. The tight fit, i.e. within about a 0.005 inch tolerance of the slot dimensions, is to prevent sand from blowing out through any space between the main core box slots and the tooling insert pieces themselves when sand is blown into the main core boxes 300 and 310 to form the main body core 100 or 200. After the main body core has been formed from the blown sand and the sand has set, it is preferred to pull out both insert pieces 304 and 308 to create accurate cavities or apertures for the lock guide lug 340 and the thrower lug 350, respectively. For instance, if these insert pieces could not be pulled out of the core box, it would be not be possible to remove the core from the main core box 310 as shown in FIG. 4B. A secondary operation to form the lock guide lug and thrower lug cavities in the core would have to be used. Accordingly, the shape and angles of the insert pieces 304 and 308 were selected carefully to release from the sand, leaving only the properly-shaped cavity in the body core 100 or 200.

FIG. 4C displays the first mold box 300 defining the first pattern 301 with a first plug 314 inserted into the shank portion 312 of the pattern 301. The first plug 314 includes a recess 315 to help form a connector (403 in FIGS. 7 and 8A). The recess 315 may further define a notched or angled surface 317 (or “notch”) to make the connector 403 asymmetrical (FIG. 8A). The other side of the plug 314 is displayed in FIG. 5A.

FIG. 4D displays the second pattern 311 with a second plug 324 inserted into the shank portion 312 of the pattern. The second plug 324 may include a corresponding recess 315 to form the other half of the connector 403. The other side of the plug 324 is shown in FIG. 5B. Alternatively, the plugs 314 and 324 may be combined into a single plug (not shown). The plugs 314 and 324 (or plug in the case of a single plug) close off the shank core 312 portions of the patterns of the mold box. The result is truncation of the shank core from the head core to form a Type-E head core 200 (FIG. 7) adapted for use with a Type-F shank core used to form the railroad coupler 254 shown in FIG. 3B.

With further reference to FIGS. 8A through 8D, the adapted head core 200 includes a male connector 403 formed by the plugs 314 and 324. The male connector 403 is insertable into a female connector 413 of the shank core 204 (FIG. 9A) corresponding to the shape of the male connector 403, to create a connection joint 533 (FIGS. 9B and 9C). As will be further explained, the connection joint 533 may be a precise, tight-fitting joint that substantially prevents shifting, and removes the concern that a T-section would form internal to the shank, which could result in hot tears at the bottom of the horn-to-shank interface.

The shank core 204 may be any of a variety of shank cores of different lengths or types, adapted with the female connector 413. The shape of the connectors 403 and 413 may be rectangular, square, oblong, tapered or any other viable shape or configuration. In an alternative embodiment, a connector formed on the adapted head core 200 may be some other type of connector, including but not limited to a female connector identical or similar to the female connector 413 shown on the shank core 204 in FIGS. 8B and 8D. Likewise, the shank core 204 may include a corresponding male connector identical or similar to the male connector 403 shown in FIGS. 7 and 8A.

As discussed, the recess 315 on the plug 314 may be used to create a notch 405 on one side of the male connector 403. The shank core may include an end having a raised portion 415 corresponding to the notch 405 of the adapted head core, creating a tight-fitting connection joint 533 that is resistant to shifting and/or misalignment when connecting the male connector 403 to the female connector 413 of the shank core. The connection joint 533 may also be structured and tapered to aid in preventing shifting and/or misalignment. The dimensions displayed in FIGS. 8C and 8D may vary, but in one example: height Y1 of the male connector 403 may be about 3 inches; height Y2 of the male connector 403 with a height of the notch 405 subtracted may be about 2 inches; height Y3 of the notch 403 may be about 0.6 inches; length X1 of the male connector 403 may be about 3 inches; length X2 of the notch 405 may be about 1.5 inches; width X3 of the female connector 413 may be about 3.2 inches; and radius R1 radius of the curved notch 405 may be about 0.7 inches. These dimensions may vary between at least 0.2 to 0.6 inches.

The connection joint 533 shown in FIG. 9C may be located within an optimum window of distance from a front face 543 of the head core 200 defined by dimensions X1 and X2. X1 may be a minimum dimension to a first end 545 of the connection joint 533 closest to the front face 543 and X2 may be a maximum dimension to a second end 547 of the connection joint 533 farthest from the front face 543. X1 may be between about 14 and 17 inches while X2 may be between about 18 and 20 inches. A mid-point of the connection joint 533 may therefore be located between about 16 and 18 inches from the front face of the head core 200.

The main body (or head) cores 100 and 200 and various shank cores 204 may be formed from a relatively low-cost molding material, such as no-bake or air-set sand, which may have a grain fineness number (GFN) in the range of 44-55 GFN. The molding material may be new sand or reclaimed sand. That is, sand that has been previously used to make castings. The reclaimed sand may be obtained by subjecting used molds to various shaking, thermal, and/or crushing operations that break down the mold into finer and finer constituent sizes until a desired grain size is obtained. Screening operations facilitate separation of the sand by size. Finally, the sand is subjected to high temperatures to burn off any residual coating or other impurities, such as the binder material. The reclaimed sand is then mixed with new binder at a ratio of about 99:1 and placed into a mold and allowed to set. Once set, the new mold, in this case the main body, head or shank core, is ready to be used within the cope and drag mold portions for casting the coupler body.

The more-refined sand may be reserved for just those portions of the mold that require improved surface finish and/or greater dimensional accuracy, such as the internal cavities, gating system, small core features and the like. Use of a no-bake or cold box process (also referred to as a cold shell sand process) may also prevent hot tears that can result when using other common processes (such as green sand molding). The no-bake or cold box process also improves dimensional accuracy and surface finish as further described in U.S. application Ser. No. 12/685,346, entitled “Use of No-Bake Mold Process to Manufacture Railroad Couplers” and filed Jan. 11, 2010, which is incorporated by this reference herein in its entirety.

FIG. 12 is a flow chart of a method for creating a main body core for casting a coupler body of a railcar coupler. At block 1200, the method includes inserting a plug into a pattern of a main body core box, the plug configured to adapt an end of the pattern of the main body core box so that a head core formed within the pattern includes a first half of a connection joint attachable to a second shank core, the second shank core different than a first shank core formed integral with the head core when the plug is not used. At block 1210, the method includes blowing sand into the main body core box. At block 1220, the method includes curing the sand to form a head core including the first half of the connection joint. At block 1230, the method includes attaching the first half of the connection joint to a corresponding second half of the connection joint of the second shank core.

The terms and descriptions used herein are set forth by way of illustration only and are not meant as limitations. Those skilled in the art will recognize that many variations can be made to the details of the above-described embodiments without departing from the underlying principles of the disclosed embodiments. For example, the steps of the methods need not be executed in a certain order, unless specified, although they may have been presented in that order in the disclosure. The scope of the invention should, therefore, be determined only by the following claims (and their equivalents) in which all terms are to be understood in their broadest reasonable sense unless otherwise indicated. 

1. A main body core box assembly for creating head cores which are attachable to various different shank cores for use in casting a coupler body, comprising: a main body core box including two halves, each half including a pattern configured to form the outer walls of a first head core having a first shank core; and a plug insertable into an end of respective patterns of the main body core box such as to form a second, alternative head core having a first half of a connection joint attachable to a second shank core that includes a second half of the connection joint, the second shank core being different than the first shank core.
 2. The main body core box assembly of claim 1, where the plug comprises a pair of plugs insertable into patterns of respective halves of the main body core box.
 3. The main body core box assembly of claim 1, where the plug includes a recess that forms a male connector as at least part of the first half of the connection joint.
 4. The main body core box assembly of claim 3, where the recess includes at least one angled surface so as to create a notch in the male connector, where the second half of the connection joint comprises a female connector including a raised surface corresponding to the notch to ensure proper orientation of the second shank core relative to the second head core when connected.
 5. The main body core box assembly of claim 1, where the first half of the connection joint comprises a female connector and the second half of the connection joint comprises a male connector corresponding to the female connector.
 6. The main body core box assembly of claim 1, where the first and second shank cores comprise Type-E and Type-F shank cores, the first and second shank cores being of different lengths.
 7. The main body core box assembly of claim 1, where a cold box process is used to make the head core within the main body core box.
 8. The main body core box assembly of claim 1, further comprising an insert piece to form an aperture for a lock guide, the insert piece slidable along a slot formed on each half of the pattern.
 9. The main body core box assembly of claim 8, where the insert piece is inserted in and withdrawn from the inside of the pattern at approximately a 90-degree angle with respect to an axis formed through a longitudinal center of the pattern.
 10. The main body core box assembly of claim 8, where the insert piece fits within about a 0.005 inch tolerance of the dimensions of the slot.
 11. The main body core box assembly of claim 1, further comprising an insert piece to form an aperture for a thrower lug, the insert piece slidable along a slot formed on each half of the pattern.
 12. The main body core box assembly of claim 11, where the insert piece is inserted in and withdrawn from the inside of the pattern at approximately a 45-degree angle with respect to an axis formed through a longitudinal center of the pattern.
 13. The main body core box assembly of claim 11, where the insert piece fits within about a 0.005 inch tolerance of the dimensions of the slot.
 14. The main body core box assembly of claim 1, where the connection joint begins between about 14 and 17 inches from a front face of the second head core.
 15. A main body core set for casting a coupler body of a railcar coupler, comprising: a shank core configured with a female connector; and a head core configured with a male connector attachable to the female connector of the shank core to form a tight-fitting connection joint, where the head core is adaptable for multiple types of shank cores, each type of shank core having a substantially identical female connector.
 16. The main body core set of claim 15, where the multiple types of shank cores comprise shank cores of different lengths.
 17. The main body core set of claim 15, where the male connector comprises a notched portion on a side thereof, and where the female connector comprises a raised portion that corresponds to the notched portion to ensure proper orientation of the shank core relative to the head core when connected.
 18. The main body core set of claim 17, where the notched portion and the raised portion have corresponding curved surfaces.
 19. The main body core of claim 15, where the shank and head cores are for a Type-F coupler.
 20. The main body core of claim 15, where the shank and head cores are for a Type-E coupler.
 21. The main body core set of claim 15, where a cold box process is used to make the head core and the shank core before interconnecting the head and shank cores.
 22. The main body core set of claim 15, where a mid-point of the connection joint is located between about 16 and 18 inches from a front face of the second head core.
 23. A method of creating a main body core for casting a coupler body of a railcar coupler, the method comprising: inserting a plug into a pattern of a main body core box, the plug configured to adapt an end of the pattern of the main body core box so that a head core formed within the pattern includes a first half of a connection joint attachable to a second shank core, the second shank core different than a first shank core formed integral with the head core when the plug is not used; blowing sand into the main body core box; curing the sand to form a head core including the first half of the connection joint; and attaching the first half of the connection joint to a corresponding second half of the connection joint of the second shank core.
 24. The method of claim 23, where a cold box process is used for curing the sand.
 25. The method of claim 23, where the plug comprises a pair of plugs, one insertable into a cope mold portion of the pattern and the other insertable into a drag mold portion of the pattern.
 26. The method of claim 23, where the plug includes a recess that forms a male connector as at least part of the first half of the connection joint.
 27. The method of claim 26, where the recess includes an angled surface so as to create a notch in the male connector, where the second half of the connection joint comprises a female connector including a raised surface corresponding to the notch to ensure proper orientation of the second shank core relative to the head core when connected.
 28. The method of claim 23, where the first half of the connection joint comprises a female connector and the second half of the connection joint comprises a male connector corresponding to the female connector.
 29. The method of claim 23, where the second shank core is selected from multiple types of shank cores of different lengths.
 30. A main body core box assembly for creating head cores for use in casting a coupler body, comprising: a main body core box including cope and drag mold halves defining respective patterns configured to form a head core having a shank core integral therewith; a first insert piece to form a first aperture for a lock guide, the first insert piece slidable along a first slot formed on each half of the pattern; and a second insert piece to form a second aperture for a thrower lug, the second insert piece slidable along a second slot formed on each half of the pattern.
 31. The main body core box assembly of claim 30, where the second slot is oriented at approximately a 45-degree angle with respect to the first slot.
 32. The main body core box assembly of claim 30, where the first insert piece is inserted in and withdrawn from the inside of the pattern at approximately a 90-degree angle with respect to an axis formed through a longitudinal center of the pattern.
 33. The main body core box assembly of claim 30, where the second insert piece is inserted in and withdrawn from the inside of the pattern at approximately a 45-degree angle with respect to an axis formed through a longitudinal center of the pattern.
 34. The main body core box assembly of claim 30, where the first insert piece fits within about a 0.005 inch tolerance of the dimensions of the first slot.
 35. The main body core box assembly of claim 30, where the second insert piece fits within about a 0.005 inch tolerance of the dimensions of the second slot.
 36. The main body core box assembly of claim 30, further comprising: a plug insertable into an end of respective patterns of the main body core box such as to form a second head core with a connector attachable to a second shank core different than the integral shank core.
 37. The main body core box assembly of claim 36, where the plug comprises a pair of plugs insertable into respective patterns of the cope and drag mold halves of the main body core box.
 38. The main body core box assembly of claim 36, where the connector comprises a male connector insertable into a female connector of the second shank core to form a secure connection joint between the male and female connectors.
 39. A main body core set for casting a coupler body of a railcar coupler, comprising: a shank core configured with a male connector; and a head core configured with a female connector attachable to the male connector of the shank core to form a tight-fitting connection joint, where the head core is adaptable for multiple types of shank cores, each type of shank core having a substantially identical male connector. 